In today's market, flat panel displays, such as liquid crystal displays (LCDs), are often enhanced with specialized films (substrates). The films may be flexible or rigid. Such films are designed to optimize optical performance, e.g., viewing contrast, increasing brightness, removing glare, enhancing color and enhancing the clarity of the flat panel display. The films are typically applied to the viewing side of the display. Application methods involve the use of an adhesive that is optically clear and pressure sensitive for easy bonding of the film (substrate) directly to the display.
Prior art methods of applying a photocurable adhesive composition to a display for bonding a substrate to the display entail application of a measured amount of the adhesive composition to the display (or substrate), placing the substrate (or display) in contact with the adhesive composition, and then photocuring the adhesive composition to afford the substrate bonded to the display through the photocured adhesive. There are problems associated with these prior art methods of bonding. First there is nothing available to contain the adhesive during photocuring to effect bonding. Consequently, adhesive can and often does flow out of the display/adhesive/substrate sandwich during bonding onto the bonding fixture such that the targeted amount of cured adhesive is not present in the bonded product which can result in increased levels of defectivity in bonded products. In addition, the adhesive or cured adhesive if present on the bonding fixture from undesirable flow out can be difficult to remove during cleanup and increase bonding process time. Second there is nothing available in prior art methods to keep a fixed distance between the display and the substrate in the bonded product. Variations in depth of cured adhesive in the bonded product can also lead to increased defectivity levels. The present invention provides a solution to reduce or eliminate the above drawbacks.